Kerkiratrobius Roca & Gaju-Ricart & Molero-Baltanás & Mendes 2010, n. gen.

Genus Kerkiratrobius n. gen.

TYPE SPECIES. — Kerkiratrobius rosanae n. sp.

ETYMOLOGY. — From the Greek noun “Kerkira” meaning Corfu. The termination “trobius” is after the ending of Petrobius Leach, 1809, type genus of the subfamily.

DIAGNOSIS

Machilidae, Petrobiinae of small size (adults 8 mm), body and appendages weakly pigmented. Body with scales but flagellum of antenna without scales.

Head: compound eyes rounded, almost as long as wide, dark in colour. Frons slightly protruded between paired ocelli; ocelli sole-shaped, slightly sublateral to compound eyes.

Antenna: almost same length, or a little shorter than body; scapus almost twice as long as wide; distal chains of flagellum formed by 8 or 9 units bearing setae, sensillae in rosette and sensory cones.

Mandible: without distinct apical teeth.

Maxillary palps:without specialized setae; last article almost as long as penultimate. Distal three articles with long numerous dorsal hyaline spines.

Labial palp: Strong, third article strongly widened and with numerous sensory cones.

Legs: all legs slender; first pair larger than the others. Legs II and III with coxal stylets; legs lacking spines on ventral surface, only hyaline spiniform setae, particularly on tarsi and tibiae.

Urosternites: coxites I-VII each with one pair of coxal vesicles and with setae, II-IX with stylets, these ending with a spine almost the same length as half of stylet or slightly shorter; sternites II-VII acute to right angled.

Genitalia: surpassing coxite IX. Paramera only on urosternite IX, slightly longer than penis, without subdivisions, distal part covered with setae that occur more or less in apical ⅔ of their length, and apically incurved, almost embracing distal portion of penis.

Penis distinctly shorter than paramera, distal part three times longer than proximal section; flattened, base of distal section with numerous little dark spines in two rows; aperture of penis subapically surrounded by setae which are not distinctly specialized.

Terminal filaments: Paracercus broken, cerci ending with a spine.

REMARKS

The lack of scales on the flagellum of the antenna, the presence of coxal stylets on legs II and III, and the presence of sensory cones of the third article of the labial palp with small lateral setae, permits placement of the new genus in the subfamily Petrobiinae.

Sturm & Machida (2001) distinguished four generic groups within the subfamily. According to the form of the sole-shaped ocelli, the new genus could belong to the Pedetontus group or to the Petrobius group. However, the new genus does not fit the former Pedetontus group, which has the distinctly articulated paramera and the penis shorter than coxite IX. Relatively to the Petrobius group, which is composed of two genera and seven species, the new genus agrees with the two European genera (Petrobius and Parapetrobius Mendes, 1980) in the non-articulated paramera, but differs from them in the length and form of the paramera, the unique penis, and also the third article of the labial palp that is widened in Kerkiratrobius n. gen.

Given the particularities of the new genus which exclude it from existing generic groups of the subfamily, and because of the absence of female specimens, we cannot make more meaningful comparisons with other genera of Petrobiinae and believe it to be most prudent to leave the genus as incertae sedis within the subfamily.